thyroid hypofunction Flashcards
lab assessment suggesting hypothyroidism
First test would be TSH if TSH is abnormal then test for T3 and T4, if TSH is high and T3 and T4 are low
Hypothyroidism 1ry, 2ry and 3ry
primary: Thyroid gland failure
secondary: pituitary gland failure
tertiary: hypothalamus failure
causes of primary hypothyroidism
Hashimoto’s thyroiditis, radioactive iodine therapy after graves disease, subacute thyroiditis ( after a while the patient enters a hypothyroidism stage)
causes of secondary hypothyroidism
hypopituitarism
causes of tertiary hypothyroidism
hypothalamic dysfunction
hypothyroidism signs and symptomps
bradycardia, weight gain, cold intolerance, rough dry skin, unexplained edema, fatigue lethargy and depression, carpal tunnel, infertility and hyperprolactinaemia
diagnosis of hypothyroidism
low free T3 and T4 and high TSH is diagnostic for hypothyroidism
presence of thyroid auto antibodies is diagnostic for ..
Hashimoto’s disease
lab findings with a secondary pituitary cause of hypothyroidism?
both low T3/T4 and low TSH , indication for brain MRI
lab findings of subclinical hypothyroidism ?
High TSH and normal free T3/T4
what is Hashimotos thyroiditis
Autoimmune disease most commonly found in children and young adults
what antibodies are present in hashimotos thyroiditis
anti thyroglobulin (Tg) and anti thyroid peroxidase(TPO) antibodies
what other autoimmune diseases may hashimotos’s thyroiditis be associated with?
pernicious anemia, adrenocortical insufficiency and vitiligo
what is schmidt’s syndrome ?
an endocrine disorder that includes a combination of primary adrenal insufficiency, autoimmune thyroid dysfunction (hashimotos) and type 1 diabetes
Hashimotos + Addison’s disease and type 1 diabetes
lab findings ini hashimoto’s thyroiditis
high levels of TSH and low levels of T3/T4, presence of anti thyroglobulin (Tg) and anti thyroid peroxidase Ab
fine needle aspirate findings of hashimotos
lymphocytic infiltration and hurthle cells
complications oh hashimotos thyroiditis
permanent hypothyroidism , and rarely a thyroid lymphoma
managmenet of hashimotos thyroiditis
start patient on L-thyroxine at 50-100mcg but if the patient has IHD then reduce the dose to 25mcg
how often should TSh levels be checked after L-thyroxine administration
after 4-6 weeks to adjust the dose of L-thyroxine
in case of secondary hypothyroidism (pituitary cause), what to monitor
monitor free T4 rather than TSH
management of hypothyroidism during pregnancy
thyroid function test must be monitored every month , l-thyroxine doses will be increased by 25-30%
Myxedema coma, what is it
is a medical emergency , characterized by stupor, hypoglycaemia , hyponatremia, hypothermia, shock and death
what is the classic presentation of myxedema coma
an obese elderly women , yellowish skin, hoarse voice, large tongue, thin hair, puffy eyes and slow reflexes , an anterior neck scar may be present (evidence of previous thyroidectomy)
what are the general measures for myxedema coma
after lab confirmation , patient should be in an ICVU setting , patient should have support ventilation as respiratory failure is the main cause of death, ABG should be monitored, support blood pressure , thyroxine medication will help with the hyponatremia and hypothermia , IV glucose should be given for the hypoglycaemic
Specific managment for Myxedema coma
L-thyroxine should be given 0.2 to 0.5 mg followed by 0.1 mg until orall is tolerated
what are the precipitating factors that may occur upon administration of thyroid hormones?
adrenal insufficiency so hydrocortisone is usually given
